Before the Falls                                       -      -      - 
(-------------------------------------------------)     - <---(M)---> E
                                                        SW     -      -

As the river bends its way around a large rock, the vegetation becomes
spare.  More and more rocks are beginning to appear in the middle of the
current, which makes you wonder what kind of change in the geography of the
river would cause this to happen.  A loud crashing sound is coming from just
around the bend, but you don't give it much thought.